By 1890, fewer than 1000 bison remained in North America after a species once numbering between 50 and 60 million across the Great Plains had been reduced by westward settlement, disappearing east of the Mississippi River by 1800 and becoming so scarce in the 1870s that even market hunters found the Great Plains void of wild game, including bison. As the western frontier vanished and the nation began changing its policies toward resource preservation and wildlife protection, conservation-minded leaders helped rescue bison from the brink of extinction. Even after Yellowstone National Park was created in 1872 as the bison's last wild refuge, poaching continued, and although federal laws were created to save the species, protection did not occur until the U.S. Army arrived in 1886. During the late 1800s, private ranchers captured bison and started herds across the Great Plains, and without this private involvement many public herds would not exist today. Men such as Pawnie Bill, William Cody, Charles "Buffalo" Jones, Charles Goodnight, Samuel Walking Coyote, and James "Scotty" Philip were early leaders of bison preservation, and their small herds helped create many public herds across the Great Plains. By the early 1900s, groups and individuals recognized that without private assistance bison would continue to be threatened, and although the federal government questioned using taxes to protect wildlife species, effort and dialogue helped start a conservation movement that led to wildlife management as a new tool for species preservation. The American Bison Society formed in 1905 with zoologist William T. Hornaday as president and Theodore Roosevelt as honorary president, pushing for legislation to protect bison and purchase land for parks and preserves. Today, bison are found in parks, refuges, and private ranches in all fifty states, have expanded beyond their historical range, and continue to grow in popularity.